Fix nested loops set_step in gcm test suite.

Signed-off-by: Mateusz Starzyk <mateusz.starzyk@mobica.com>
diff --git a/tests/suites/test_suite_gcm.function b/tests/suites/test_suite_gcm.function
index 86f7fb9..109f300 100644
--- a/tests/suites/test_suite_gcm.function
+++ b/tests/suites/test_suite_gcm.function
@@ -194,11 +194,9 @@
 
         for( n1 = 0; n1 <= src_str->len; n1 += 1 )
         {
-            mbedtls_test_set_step( n1 );
-
             for( n1_add = 0; n1_add <= add_str->len; n1_add += 1 )
             {
-                mbedtls_test_set_step( n1_add );
+                mbedtls_test_set_step( n1 * 10000 + n1_add );
                 if( !check_multipart( &ctx, MBEDTLS_GCM_ENCRYPT,
                                     iv_str, add_str, src_str,
                                     dst, tag,
@@ -248,10 +246,9 @@
 
             for( n1 = 0; n1 <= src_str->len; n1 += 1 )
             {
-                mbedtls_test_set_step( n1 );
                 for( n1_add = 0; n1_add <= add_str->len; n1_add += 1 )
                 {
-                    mbedtls_test_set_step( n1_add );
+                    mbedtls_test_set_step( n1 * 10000 + n1_add );
                     if( !check_multipart( &ctx, MBEDTLS_GCM_DECRYPT,
                                         iv_str, add_str, src_str,
                                         pt_result, tag_str,